(1) Field of the Invention
The present invention relates to a coaxial connector for use in mechanical connection of a coaxial cable and, in particular, to a coaxial connector of a thin type which has a diameter slightly larger than the coaxial cable. The present invention also relates to a coaxial multicore receptacle having pin contacts each mating with such a thin-type coaxial connector.
(2) Description of the Prior Art
In transmission of electrical signals, a coaxial cable is used which comprises a central conductor insulated from an outer conductor by an inner insulator, and an outer insulator jacket. A coaxial connector is used to connect the coaxial cable to an electric device.
Among known coaxial connectors, a small one of a thin type is used together with a coaxial multicore receptacle having a plurality of pin contacts for mating with such thin-type coaxial connectors.
JP-U-62-66187 (Jikkaisho 62-66187) discloses such a thin-type coaxial connector which comprises a central contact, for example, female contact to be connected with the central conductor of the coaxial cable by soldering, an insulator holder of two half-cylinders for holding the central contact together with the inner insulator of the coaxial cable, a ferrule to be mounted on the outer jacket of the coaxial cable, and an outer conductor sleeve fitted onto the insulator holder and the ferrule. The ferrule and the outer sleeve tightly clamp the outer conductor of the coaxial cable therebetween.
In the coaxial connector, the central conductor and the central contact are connected by soldering and the holder is constituted by a combination of two half-cylinder parts. This resultantly makes the assembling operation complex and confusing. Further, since the half-cylinder parts are low in resistance to deformation caused on handling, they have a problem of a high occurrence rate of inferior ones.
Moreover, the soldering process for connecting the central conductor and the central contact requires a high skilfulness for performing the process.
In the known thin-type coaxial connector, the female contact has spring contact portions which are formed at an axial end of the central contact. Therefore, the spring contact portions easily touch any external objects and thereby are easily deformed upon handling the central contact before and during assembling the coaxial connector. Further, a central axis of the contact spring portions should be coincident with a central axis of an opening for receiving the pin contact so that the pin contact reliably mates with the spring contact portions. These make assembling operation of the coaxial connector complex and difficult.
The coaxial multicore receptacle is used for connecting an electric circuit device such as a print circuit board or a large-scaled integrated circuit element to a plurality of coaxial cables through the thin-type coaxial connectors. A known coaxial multicore receptacle is disclosed in U.S. Pat. No. 4,611,867 which comprises a plurality of ground pins set upright on an insulating substrate and arranged in a matrix pattern, a plurality of signal pins set upright on the substrate each being located at the center of each box of the matrix pattern, first metallic lattice boards provided perpendicularly to the substrate each being positioned correspondingly to and above each column of the ground pins, and second metallic lattice boards provided perpendicularly to the substrate each being positioned correspondingly to and above each row of the ground pins. The first and second lattice boards cross one another orthogonally to define angular coaxial connector insertion holes surrounded by the boards and arranged in the matrix pattern. Each of the first lattice boards is formed with notches in the end portion on the side of the substrate to provide ground elements which are in elastic contact with the corresponding ground pins. As a coaxial connector is inserted into one of the coaxial connector insertion holes, a central contact of the coaxial connector comes into contact with the corresponding signal pin. Each of the first lattice boards is also formed with coaxial ground plates which come in elastic contact with outer conductor sleeves of adjacent coaxial connectors. Thus, signals pins are shielded by the coaxial ground plates.
In one application of the coaxial multicore receptacle, several power source pins are used in place of the ground pins on the substrate. In that case, several ones of the ground elements must be cut away at positions corresponding to the power source pins and insulating caps must be used to cover the power source pins. This tends to introduce an error in cutting ground elements and failure in covering the power source pins with insulator caps, in particular, when the ground pins and power source pins are arranged complex.
Further, the known coaxial multicore receptacle uses the second lattice boards in addition to first lattice boards and is therefore complicated in the structure.